Hypoglycemic effects of black brick tea with fungal growth in hyperglycemic mice model

Abstract

Dark tea (containing Eurotium cristatum) and black tea have hypoglycemic effects. The black brick tea with fungal growth is obtained from black tea by adding E. cristatum, followed by steaming, pressing, fungal growth, and drying. However, the hypoglycemic effects of black brick tea are still unexplored. Here, we used black brick tea with fungal growth and black tea as raw materials to study their hypoglycemic effects in a hyperglycemic mice model. Both these types of black tea could lower the content of blood glucose and increase the content of hepatic glycogen by upregulating the proteins and mRNA expression of phosphatidylinositol-4,5-bisphosphate3-kinase, glycogen synthase, protein kinase B and phosphoinositide-dependent protein kinase-1 and downregulating the protein and mRNA expression of glycogen synthase kinase 3β. These regulatory steps were followed by high activities of glutathione peroxidase and superoxide dismutase and low content of malondialdehyde. These teas can promote blood glucose transport and absorption by upregulating the protein and mRNA expression of insulin receptor substrate-1 and glucose transporter-2 and stimulate glycolysis by upregulating the protein and mRNA expression of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2. Our study suggests that the black brick tea was more effective than the black tea in terms of hypoglycemic.